Testing texturized yarn

ABSTRACT

Method and means for obtaining a comparative assessment of crimping forces of textured yarn wherein the yarn is advanced between two sets of feed rolls, is heated in the region therebetween and the magnitude of its crimping force is determined in such region.

United States Patent 1 1 Denton [451 Apr. 10, 1973 [54] TESTINGTEXTURIZED YARN [75] Inventor: Michael James Denton, Didsbury,

- England 731 Assignee: Heberlein & Co. AG, Wattwii, s1.

Gall, Switzerland 22 Filed: May 4,1971

21 Appl.No.: 140,146

[521 LS. Cl ..l3/160, 28172.1 [51] Int. Cl. ..G0ll 5/06 [58] Field ofSearch ..73/160, 144, 15.6,

[56] References Cited UNITED STATES PATENTS 3,333,467 8/ i967 Hoskins..73/ 160 1,961,755 6/ 1934 Foster ..73/l44 FOREIGN PATENTS ORAPPLICATIONS 3/ 1965 Canada 1. 128/62 Primary Examiner-Louis R. PrinceAssistant Examiner-Denis E. Corr Attomey-John Thomas Celia [57] ABSTRACT8Clailm,2DrawingFigures PAIENTE APR 1 01913 I N VEN TOR. Mama Jmss Dinraw TESTING TEXTUZED YARN This invention concerns the testing of yarns,and more particularly, the continuous measurement of crimping force intextured yarns. By textured yarns is meant yarns in which the individualfilaments or fibers ther'eof have been subjected to a process whichdeforms them, the deformations being such that they are removed, atleast to some extent, when the yarn is extended but which, because oftheir tendency to return, then give rise to a contractile force in theyarn. The tendency of the deformations to return is accentuated by theapplication of heat to the yarn. By crimping force is meant thecontractile force arising in the yarn due to this tendency of thedeformations to return when the yarn is restrained from freelycontracting in length under the influence of that force.

A method of, and means for, obtaining a comparative assessment ofcrimping force is desirable in order to facilitate textured yarn qualitycontrol, and also in order to make some prediction of the likelybehavior of textured yarn in fabric. When textured yarn is made up intofabric, it is usual for the fabric to be subjected to a relaxationtreatment, that is to say, a treatment usually under wet or hotconditions, or both, which causes an increase in yam contractile forcethat is eventually balanced by the restrictions imposed by the fabricconstruction. For this reason, the testing of yarn to give measurementof crimping force at a fixed retraction offers a means of predicting theprobable behavior of the yarn when made up into fabric.

tribution to the art may be better appreciated. There are, of course,additional features of the invention that will be described hereinafterand which will form the subject of the claims appended hereto. Thoseskilled in the art will appreciate that the conception upon which thisdisclosure is based may readily be utilized as a basis for the designingof other structures for carrying out the several purposes of theinvention. It is important, therefore, that the claims be regarded asincluding such equivalent construction as do not depart from the spiritand scope of the invention.

A specific embodiment of the invention has been chosen for purposes ofillustration and description, and is shown in the accompanying drawings,forming a part of the specification, wherein:

FIG. 1 is a diagram showing one apparatus for testing textured yarnaccording to the invention; and

FIG. 2 is a diagram showing another apparatus for testing textured yarnaccording to the invention.

Referring first to FIG. 1, the yarn Y is shown being travelledcontinuously from a source of supply (not shown) to a take-up 10. Duringits travel, the yarn It is the object of the present invention toprovide a I method of, and apparatus for, testing textured yarn which isreasonably simple, reliable and inexpensive.

According to the present invention, a method of testing a textured yarnwhereby to obtain measurement of the crimping force comprisescontinuously travelling the yarn through a first zone wherein a fixedpre-tension is applied thereto, and then through a second zone in whichit is heated and partially relaxed, by a given amount, the length ofyarn in the second zone being looped around a weighted member which isso arranged that it will assume a position which is dependent on themagnitude of the crimping force in the yarn in the second zone.

The invention also contemplates apparatus for determining the crimpingforce in a textured yarn comprising means for continuously travelling atextured yarn from a source of supply to a collection position whichincludes a first set of feed rolls, and a second set of feed rolls toover-feed the yarn into the region therebetween, there being apre-tensioning device in advance of the first set of feed rolls, and,between the first and second sets of feed rolls, a yarn heater, and aweighted member around which the yarn can be looped, and which is soarranged that it will assume a position dependent on the magnitude ofthe crimping force in the yarn.

It is evident that any device, of sufficient sensitivity, which isnormally used for measuring the tension in running textile yarns couldalso be used for measuring the crimping force in the heated zone.

There has thus been outlined rather broadly the more important featuresof the invention in order that the detailed description thereof thatfollows may be better understood, and in order that the presentconpasses first over a pre-tensioner 12, for example of the hysteresistype, which is adjustable so that a fixed pretension may be applied tothe yarn Y, then through a mechanical tension meter 14, for example ofthe zivy type; then through a first set of feed rolls 16; thenvertically downwardly through a tubular electric heater 18; then over apulley 20 forming part of an indicating device which will be describedin more detail hereinafter; then vertically upwardly through the heater18; and then through a second set of feed rolls 22. The pulley 20 ismounted at the end of a pivotal arm 24 which has, at the other side ofits pivot, a counterweight 26. Attached to the arm 24 near the end whichcarries the pulley 20 is one end of a hanging chain 28, the upper end ofwhich is secured to an adjustable roller arrangement 30. The arm 24moves, between the pulley 20 and the point at which the end of the chain28 is attached, over a calibrated scale 32.

In use, with the textured yarn running through the apparatus asillustrated and as described, and with the heater 18 switched on, acertain crimping force will arise in the yarn forming the loop betweenthe respective feed rolls 16 and 22, provided the yarn is suitablypre-tensioned by the tensioner l2, and provided the feed rolls l6 and 22are arranged to give a suitable over-feed. Under equilibrium conditions,the arm 24 will indicate a certain reading on the scle 32. When runninga different yarn under the same operating conditions and which has adifferent crimping force, the arm 24 will assume a different positionand, therefore, give a different reading on the scale 32. The pulley 20will obviously assume a higher or lower position according to whetherthe crimping force in the yarn is the greater or the lesser, thisposition being a balanced one when a sufficiently additional amount ofthe chain 28 has become available for weighting the arm 24 (in the casewhere the pulley 20 rises), or when a sufficiently diminished amount ofthe chain 28 is available for weighting the arm 24 (in the case wherethe pulley 20 setting, to enable the lever to work within the limits ofthe scale 32, which latter then gives a fine reading.

Referring now to FIG. 2, an alternative form of apparatus is shown. Inthis case, the yarn Y again passes from a source of supply (not shown)to a take-up 34. In its path, it travels successively through apre-tensioning device 36; through a first set of feed rolls 38; througha tubular electric heater 40; around a pulley 42 and through a. secondset of feed rolls 44. In this case, the yarn lies at an angle to thevertical direction in its approach to and departure from the pulley 42.The pulley 42 again forms part of an indicating system, it beingweighted by a fixed weight W, supported on a balanced light arm 46.

In use, it will be clear that the system is self-compensating fordifferent crimping forces in the yarn being tested, as the tension inthe yarn approaching and departing from the pulley 42 is W (2 Cos where0 is the angle which the yarn approaching and departing from pulley 42makes with the vertical direction. Thus, comparative assessments ofcrimping force in different yarns may be made by noting the position ofthe weight W against a scale 47.

Instruments of the type just described do, of course, need calibrationfor the selected processing parameters. l have found that a verysuitable over-feed is 6 per cent and a very suitable temperature for theheating device is about 120 degrees centigrade with a yarn speed lyingbetween five and fifteen meters per minute. The selected pre-tensionshould not be excessive, otherwise the yarn would be caused to slip onthe feed rolls.

I have found that the instruments described with reference to FIGS. 1and 2 are capable of providing a measurement of crimping force, thusenabling the quality of such yarns as false-twist textured yarns ofnylon and polyester to be assessed. The instruments prove reasonablyresponsive to changes in the levels of yarn processing variables, aswell as to changes in yarn quality arising from other causes. Theinstruments are relatively insensitive to small changes in thetemperature of the instrument heater, but quite sensitive to changes inthe pre-tension applied to the yarn, and for this reason the lattershould be quite carefully controlled. Changes in ambient conditions werefound to have little effect.

What I claim is:

1. Method of testing textured yarn to obtain a measurement of itscrimping force, comprising: continuously advancing the yarn through afirst zone, applying a fixed pre-tension to the yarn in said first zone,advancing the yarn through a second zone, heating the yarn in saidsecond zone, partially relaxing same, applying a known force to the yarnin said second zone by suspending a weight therefrom to exert tensionthereon to cause same to assume a path dependent upon the magnitude ofthe yarn crimping force, the disposition of said weight depending on theconfiguration of said path, said tension varying in correspondence withchanges of said disposition to permit determination of said crimpingforce from said disposition.

2. Method according to claim 1, wherein the yarn is advanced through aheater in said second zone and is looped back to again advance throughthe heater, the yarn loop supporting a weight, which is self-adjustingto ii li 352.22%? u ig t claim 1, wherein the yarn is advanced at aspeed of the order of 5 to 15 meters per minute.

4. Method according to claim 3, wherein the yarn is overfed in thesecond zone and is heated to a temperature of the order of about C.

5. Method according to claim 4, wherein the yarn is overfed by about 6percent.

6. Apparatus for determining the crimping force in a textured yarn,comprising: means for continuously advancing a textured yarn from asource of supply to a collection position, said means including firstand second sets of feed rolls, said sets of feed rolls being operable tooverfeed the yarn into the region therebetween, pre-tensioning means inadvance of the first set of feed rolls, means for heating the advancingyarn in the region between said sets of feed rolls, and means in saidregion for determining the magnitude of the crimping force in the yarn,said last-mentioned means including a weight acting on the yarn to causeit to assume a path dependent on the magnitude of its crimping force,said weight exerting tension on said yarn which tension variably dependson the disposition of said weight, said tension thereby balancing saidcrimping force and said disposition corresponding to variations of saidpath.

7. Apparatus according to claim 6, wherein the yarn passes verticallythrough said heater, is looped around said weight and again passesvertically through said heater.

8. Apparatus according to claim 6, wherein said first set of feed rollsand said weight are arranged whereby the yarn passes through said heaterat an angle to a vertical plane through said weight, and said weight andsaid second set of feed rolls are arranged whereby said yarn advancesfrom said weight to said second set of feed rolls at an angle to saidplane equal to said firstmentioned angle.

1. Method of testing textured yarn to obtain a measurement of itscrimping force, comprising: continuously advancing the yarn through afirst zone, applying a fixed pre-tension to the yarn in said first zone,advancing the yarn through a second zone, heating the yarn in saidsecond zone, partially relaxing same, applying a known force to the yarnin said second zone by suspending a weight therefrom to exert tensionthereon to cause same to assume a path dependent upon the magnitude ofthe yarn crimping force, the disposition of said weight depending on theconfiguration of said path, said tension varying in correspondence withchanges of said disposition to permit determination of said crimpingforce from said disposition.
 2. Method according to claim 1, wherein theyarn is advanced through a heater in said second zone and is looped backto again advance through the heater, the yarn loop supporting a weight,which is self-adjusting to balance the crimping force.
 3. Methodaccording to claim 1, wherein the yarn is advanced at a speed of theorder of 5 to 15 meters per minute.
 4. Method according to claim 3,wherein the yarn is overfed in the second zone and is heated to atemperature of the order of about 120*C.
 5. Method according to claim 4,wherein the yarn is overfed by about 6 percent.
 6. Apparatus fordetermining the crimping force in a textured yarn, comprising: means forcontinuously advancing a textured yarn from a source of supply to acollection position, said means including first and second sets of feedrolls, said sets of feed rolls being operable to overfeed the yarn intothe region therebetween, pre-tensioning means in advance of the firstset of feed rolls, means for heating the advancing yarn in the regionbetween said sets of feed rolls, and means in said region fordetermining the magnitude of the crimping force in the yarn, saidlast-mentioned means including a weight acting on the yarn to cause itto assume a path dependent on the magnitude of its crimping force, saidweight exerting tension on said yarn which tension variably depends onthe disposition of said weight, said tension thereby balancing saidcrimping force and said disposition corresponding to variations of saidpath.
 7. Apparatus according to claim 6, wherein the yarn passesvertically through said heater, is looped around said weight and againpasses vertically through said heater.
 8. Apparatus according to claim6, wherein said first set of feed rolls and said weight are arrangedwhereby the yarn passes through said heater at an angle to a verticalplane through said weight, and said weight and said second set of feedrolls are arranged whereby said yarn advances from said weight to saidsecond set of feed rolls at an angle to said plane equal to saidfirst-mentioned angle.